The present invention relates to a process for the hydrocavitation, electromagnetic, electrocoagulation, hydrocyclone and flocculation treatment of water and wastewater for purposes of reuse. Water covers more than 70% of the earth's surface. But only 2.5% is freshwater. Two-thirds of that is locked up in ice caps and glaciers. Freshwater accessible in lakes, rivers, and streams is just six-thousandths of one percent of the world's total water. Climate change, drought, population growth and pollution are stressing the planet's freshwater supply. This will most likely mean that politicians, scientists and the general public will have to make tough choices to adapt to a world where water could outstrip fuel as the most prized commodity.
In March of 2012, it has been estimated that seven billion people were living on planet earth. They use nearly 30% of the world's total accessible and renewable supply of water. By 2025 this value may reach 70%. Yet billions of these same people lack basic water supply services; estimates of 5 million people die each year from water-related diseases (e.g., typhoid and cholera). Water has also become a basis for regional and international conflict.
A great deal of world-wide water use is non-consumptive which means the water is returned to the environment. Usually this water is contaminated with an array of contaminants, whether it is used for agriculture, domestic consumption, or by industry. The world's water supply problems are further complicated by increasing world population and pollution.
Wastewater treatment, recycling and reuse is an increasing necessity, as shortages, pollution and restriction on domestic users and commercial entities by government require that new, economically feasible and readily adaptable technologies be developed for increasing supply.
Industry produces an array of pollutants or contaminants. These include detergents, dyes, pharmaceuticals, petroleum products, oil, grease, heavy metals, biological and non-biological organic products, food and beverage wastes. These wastewaters are most often discharged directly to the sewer system, rather than treated and recycled for reuse by industry. In many cases, such discharge is waste of a valuable resource when one considers that technology is available to economically treat and recycle such wastewater streams.
In many parts of the world, especially developing countries, economical and readily adaptable methods to treat water for domestic consumption is severely lacking. Surface waters are often contaminated with untreated human and animal waste, water borne disease organisms, heavy metals and dangerous organic products, including petroleum. Groundwater from wells and boreholes is often contaminated with high concentrations of heavy metals, such as arsenic.
A wide range of wastewater treatment techniques are known. These include biological processes for nitrification, denitrification and phosphorus removal, as well as, a range of physico-chemical processes. The physico-chemical processes include filtration, ion exchange, chemical precipitation, chemical oxidation, carbon adsorption, electrocoagulation, ultrafiltration, reverse osmosis, electrodialysis, and photo-oxidation.
Treatment of wastewater by electrocoagulation (“EC”) has been practiced for most of the twentieth century. It has achieved limited success in most instances. The technology is increasingly being used in Europe for the treatment of industrial wastewater containing heavy metals. In North America the EC process has been employed to treat wastewater from the pulp and paper industry, effluents from the mining industry and metals processing industry. This technology has been used to treat wastewater containing food stuffs, suspended particles, dyes, petroleum products, animal fats, landfill leachates, solutions of heavy metals, polishing compounds, phosphorus, organic matter, pesticides and synthetic detergents.
Electrocoagulation is the process that occurs within an electrolytic reactor or cell. The reactor is a cell containing an anode and a cathode. When connected to an external power supply, the anode is oxidized and the cathode is passivated and reduction occurs, producing gases such as hydrogen. In practice, the electrodes are usually parallel metal plates that serve as monopolar electrodes, which may be of the same or different metal. The electrodes are attached to a DC power supply that allows current and voltage adjustment. Under current flow to the anode, an appropriate metal is oxidized and cations of the metal are released into the flowing wastewater. The anode is referred to as the “sacrificial electrode”, since it is ultimately consumed in the reaction. The ions produced in this reaction neutralize or destabilize contaminants within the wastewater, which allows them to coagulate and precipitate.
Known technology for such systems suffers from a number of disadvantages. These include:                Lack of Adaptability. Most systems are designed for single purpose application and are fixed in their design for treating a specific wastewater contaminant and/or treating at a specific flow rate.        Lack of Efficiency. Most systems lack the capability to efficiently treat a broad spectrum of wastewater contaminants.        
Electricity has been used to treat and condition water since the late 1800's. Significant improvements have been made in treatment technology periodically over the last century. Current knowledge development and improvement in the water treatment art, demonstrated herein, has shown that the EMC/F System which incorporates Electrocoagulation, Magnetic, Cavitation and Flocculation subsystems provides a significant advance in water treatment technology. Significant research demonstration, testing, development and implementation show a novel and remarkably adaptable technology that can be appropriate for processing and treating various difficult-to-treat industrial wastewaters. Using the advanced EMC/F and traditional separation technologies, the consumption of chemicals and energy and associated costs for water treatment are significantly reduced. Such characteristics would allow EMC/F to be classified as a “Green Technology”. In addition, the area dedicated to water treatment (plant footprint) for the EMC/F is smaller than for traditional technologies. The ultimate objective in many instances is that the treated water be clean enough to meet reuse standards in a facility or activity which would further reduce cost and allow conservation of treated water supplies and those of untreated supplies (rivers, reservoirs, and lakes).
History. Electrocoagulation and electroflocculation have been used by many industries over the last century, principally mining, metal finishing and fabrication. Energy companies developed high flow systems to treat the wastewater from coal slurry pipelines (Westinghouse, General Electric). Metal finishing industries have used both flow through and batch systems for several decades. Enviro-Chem (Monsanto) modified the Russian membrane EC technology that separates the anolyte (flow from anode) and catholyte (flow from cathode) with a porous ceramic membrane. Controlling the composition of the influents and the electrical currents allows the production of “activated” water that can be used to sterilize or treat wastewaters. The Germans were first to note the ability of electrically processed water to carry energy and provide treatment.
Electrical treatment of water has been practiced in several countries for many years. Eastern Europe, Germany and Argentina are notable for the use of electrical energy for various purposes in water treatment. Electroflocculation is often used for removal of suspended solids from surface water supplies prior to chemical treatment to produce drinking water. On occasion, an induced current is used to remove microbes as a final step in drinking water distribution. Electroflocculation is not widely used as the primary treatment for either drinking water or wastewater.
A well known characteristic of electrical energy is magnetism. Many boilers operate with electromagnets on the condensate return or feed water lines. The energy is critical to the prevention of scaling from calcium and magnesium in the feed water. A magnetic field of a precise force around the pipes has been shown to reduce scaling by controlling the speciation of these atoms as they precipitate from the water. The predominant species of calcium precipitated, post-magnetic treatment, is aragonite which does not form scale. Cavitation treatment, followed by Magnetic and Electrocoagulation treatments and finally Hydrocyclone treatment to remove larger floc particles is a unique and novel concept and process with all the above described technologies incorporated into a single system, as described herein. This single system is further known as the EMC/F technology.
As a technology with a long history and a well known capability, electrocoagulation has not been in the mainstream of water treatment. The high cost of replacing electrodes, the difficulties with production of reliable, steady state power and the general misunderstanding of electrical treatment have hindered its acceptance. In addition, a number of unscrupulous companies proliferated in the late 1990's promising miraculous treatments and not delivering quality equipment. The technology appears to be very simple and it is easy to effect treatment on bench scale or batch systems. Treatment with electricity is complex and many variables need to be addressed and accounted for to produce a successful full scale treatment unit.
In the following pages, the unique EMC/F technology will be described. This advanced system incorporates technologies with all of the physical, chemical and electrical concepts described. The EMC/F system utilizes the DC electrical energy, cavitation, magnetic, electrocoagulation, and hydrocycloning to effect advanced wastewater treatment. This novel and unique technology process is a major step forward in the field and provides the broadest applicability for the reduction in the concentration of organic, inorganic, gaseous and biological contaminants found in wastewater and in water supplies.
Water is the universal solvent and has been the fundamental component of industrial and petrochemical development. Within the last half century, the realization of a finite water supply has developed. Regulatory response has been the requirement for increasingly stringent treatment of water before use or release. The properties that make water a fundamental and important part of life also make it a difficult medium to purify. Contaminants can be dissolved, colloidal, suspended, emulsified or any combinations thereof.
Water forms strong intermolecular bonds due to the polarity of the molecules. These bonds hold contaminants in the solution matrix or water in the contaminant matrix. Energy must be externally applied in the form of magnetic, electrical and physical energy to destabilize such systems and free the water and, simultaneously, allow contaminants to coagulate and flocculate from solution.
As a polarized solvent, charged water particles cause ions to dissociate and become part of the solution. For example, sodium chloride (NaCl) is a solid in the absence of water. However when dissolved in water it exists in solution in the dissociated ionic form: Na+1 and Cl−1. Attractive forces that hold materials in the water and cause water molecules to align based on charge proximity also affect the physical properties of water. Water can absorb and hold significant amounts of energy with few changes in physical properties.
Water Treatment. Water treatment has changed little over the last century. In general the technologies have been based on chemical additions to create insoluble products from contaminants, followed by filtration to capture contaminants. Where organic components are present, biological, absorption or vapor extraction mechanisms have been added to the treatment process as appropriate. No new or dramatic approach has been brought to the industry for forty years or more since the advent of Reverse Osmosis which employs high pressure filtration. Improvements in chemicals (e.g., particularly polymers) and genetically engineered or specifically cultured biological organisms are the most common changes in process.
EMC/F technology offers a superior alternative to traditional water treatment. The EMC/F system is differentiated from typical electrocoagulation and electroflocculation treatments. To address this issue, it is critical to understand the nature of water treatment.
Contaminant chemicals in wastewater may be categorized into a number of categories. These categories are:                Organics—fat, oil, grease, hydrocarbons, solvents, petrochemicals, food products, algae, bacteria and other biological organisms,        Total Suspended Solids—non-dissolved inorganic materials in colloidal suspension or dispersion; also known as TSS, and        Total Dissolved Solids—chemicals of a molecular or atomic level dissolved in water and intimately associated with water molecules; also known as TDS.        
Organic materials are most commonly treated through biological (bacterial) degradation followed by settling and filtration. Air (oxygen) may be provided to enhance the biological activity. Nutrients may be added to optimize the metabolism and hence the decomposition of the contaminants. Ideally, the contaminants are converted to biomass, CO2 and water. The biomass is removed in the filtration step with incorporated contaminants. Organics that are not a food source to the organisms are removed from the water by mechanical means or through concentration on media that is further processed or stripped and concentrated as vapor. Low concentrations of volatile organic carbons may be removed by using diffused aeration, activated carbon filters, UV light and/or ozonation.
All processes identified require sizeable structures to accommodate flow or residency times. Current facilities represent significant capital expenditures and often receive discharges from industry that do not meet current water quality standards. Such facilities are forced to pre-treat their effluent and, in some cases, pay fees (surcharges) to discharge over the legal standards.
Total Suspended Solids (“TSS”) are materials that can often be filtered from the wastewater. Filtration of large quantities of water is capital intensive and time consuming. More efficient separation can be achieved by altering the dispersion forces through centrifugation. These systems are complex and expensive. Chemicals are readily available that react with the suspended solids and/or the water to enhance the separation and removal. Chemical treatment is the mainstay of the industry and the basis for most treatment regulation. Additives function first to combine with the suspended solids and neutralize electrical charges which then allow larger particles to form that are easier to precipitate from solution. Chemicals, such as surface active agents, also are added to reduce the surface tension or polar attractiveness of the water allowing particles to move with less resistance.
Chemical treatment has advanced through the creation of new products (polymers) that react more effectively with suspended solids. Some chemical treatments leave residual materials in the water. Overdosing is often practiced to accommodate variations in the wastewater and can be a costly process.
Total Dissolved Solids (“TDS”) may be treated with chemical addition but most often require additional sophisticated treatment methods after the suspended solids are removed. Clarified wastewater can be treated with ion exchange resins, mixed resin beds, microfiltration, ultrafiltration, electrodialysis or reverse osmosis. Resins are chemicals that that are used to attract and capture certain ions or molecules. Each resin is ion specific, therefore a mixture of resins is needed to react with and remove the variety of ions found in wastewater. Resins eventually become saturated and must be treated to remove the captured ions. The resin wash is a concentrated wastewater that also must be treated.
Microfiltration, ultrafiltration and reverse osmosis (“RO”) are mechanical separation processes conducted under high pressure. Each utilizes specially formulated membranes that allow smaller water molecules to pass through while capturing the larger contaminant molecules. Each process then produces a concentrate stream that must be managed and disposed.
The resins and membranes will produce the highest purity water, although at a high cost. Industrial and bottled water needs are met by some combination of these techniques. De-mineralized and ultrapure water used for boiler feed, pharmaceutical production, and in chemical reactions, are produced by these techniques.
EMC/F system may be thought of as located between chemical/biological and de-mineralized/RO treatment systems. The technology is extremely efficient (>95% removal) on suspended solids and some dispersed oils and grease as well as most inorganic dissolved solids. EMC/F treatment is not appropriate for “stand-alone” treatment of alcohols, sugars, amines, amides, pesticides, herbicides, chlorinated hydrocarbon solvents and complex surfactants.
EMC/F technology will enhance most treatment systems in use and can be a powerful tool in treatment systems under design. The versatility and consistent response of EMC/F allows for a wide range of applications and less concern for wastewater consistency. Water treatment free from dosage and flow limitations or monitoring allows more flexibility of design and reduced costs of attention, maintenance, supplies, reagents, and down-time. High purity systems benefit from pretreatment by EMC/F technology. Efficient removal of most contaminants would serve to extend resin or membrane life, reduce maintenance and downtime and increase capacity of systems. Per unit costs for treated water would be reduced in these applications.